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LITTLE BLUE BOOK NO. 1 "3 ^3Edited by £. Haldeuian-Julius X Oi)

Principles of

ElectricityMaynard Shipley

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LITTLE BLUE BOOK NO. 1 "5 "5

Edited by £. Haldeman-Julius A %J %3

Principles of

ElectricityMaynard Shipley

HALDEMAN-JULIUS COMPANYGIRARD, KANSAS

Copyright, 1925,

Haldeman-Julius Company.

PRINTED IN THE UNITED STATES OF AMERICA

PRINCIPLES OF ELECTRICITY

CONTENTS

Chapter Page

1. "What Is Electricity?" 5

2. Magnetic Phenomena 13

3. Pioneers in Electromagnetic Theory 19

4. Theories of Electricity 30

5. Modern Magnetic Theory 41

6 Proofs that Electrons Are Atoms of Elec-

tricity 44

7. The Discovery of Wireless Telegraphy. . .55

PRINCIPLES OF ELECTRICITY

CHAPTER 1

"what is electricity?55

Many persons who have devoted no time to

the study of physics wonder what the force is

that drives the street-car along—turning its

wheels, while at the same time furnishing in-

candescent lamps (light) for the passengers.They have been told, of course, that the "pow-er" used is "electricity", generated by dynamos"at the power-house", and conveyed to the rap-idly moving car by the overhead wire.

"Electricity: yes, but what is electricity?"This is a natural and perfectly legitimate ques-tion for a layman to ask.

Scientists and philosophers are asking thesame question. But they understand quite wellthat it is like asking: "What is matter?" Veryprobably the average inquirer does not ask thequestion, "What is electricity?" in the samespirit. We can answer one question no betterthan the other, if the ultimate nature of eithermatter or electricity is what the inquirer hasin mind.For matter, in the last analysis, is electricity.

Yet the same person who might ask: "What is

electricity?" would not think of asking: "Whatis matter?" He thinks he knows what matter is

—his common sense tells him that matter is

what it appears to he. "Matter's matter, andthere's an end of it."

And just so the physicist insists upon his

6 PRINCIPLES OF ELECTRICITY

common-sense right to reply: "Electricity is

electricity." It is what it appears to him to be.

And it appears to be a form of energy, or amode of motion.

Thales, the reputed founder of Greek scienceand philosophy, would call electricity "the soulof the universe", because it "endows all thingswith motion". This "soul", interpenetrating all

matter—if not constituting it—is by nature al-

ways moving—it is self-moving; motion is partof its very essence. In the lodestone, saidThales, "it moves iron."*

As has been said so many times before,Thales was the first to call attention to thefact that amber (fossilized resin), when rubbedwith wool or fur, possesses the curious propertyof attracting small particles, such as straw,pith, lint, dried leaves, etc.;—though there is

no reason to suppose that he was the discovererof this phenomenon. He called the amberelektron; and today we call the indivisible

corpuscles, or natural unit charges of negativeelectricity, electrons—the true atoms of elec-

tricity.

But hard rubber, or sealing-wax, is just as"mysterious" as the lodestone (magnetite

—

natural magnetic iron). Rub the sealing-waxwith fur, and it will exhibit all the peculiarproperties of the lodestone. Rub glass withsilk, and it, too, becomes a lodestone in effect.

Hf a light piece of iron is placed near a magnet,it moves to the magnet and clings to it ; but if themagnet is the lighter of the two bodies, it movestoward the piece of iron.

PRINCIPLES OF ELECTRICITY 7

The ancient Greek philosophers could not ex-

plain these phenomena in precise terms.Empedocles (born between 500 and 480 B. C.)

accounted for the attraction of iron to the mag-net on the hypothesis that "emanations" or"effluences" from the magnet penetrate intothe "symmetrical pores" of the iron, drawingthe iron itself and holding it fast. The concept"electricity" was unknown to the Greeks. Butit is possible that Empedocles had in mind somesuch "effluence" or "emanation" as the "fluid"electricity of Benjamin Franklin (1706-1790)and his successors.

The soul-force (Amoving power") of Thales

—

always moving and causing movement—and the"effluences", of Empedocles have become the"field of force" of Faraday, Sir J. J. Thomson,and Sir Oliver Lodge. The self-moving "soul"of nature, manifest in the lodestone, or actingon the lodestone, or on the particles said to be"attracted" by the lodestone, is but a synonymfor the lines of force of the magnetic field of

modern physics. Thales and Empedocles spokein the language (terminology) of their day andage. The "emanations" of Empedocles are the"corpuscles" of Thomson—a body becomingpositively electrified by "losing some of its

corpuscles", and hence capable of drawingnegatively charged particles to itself.

Electricity and magnetism are related butndt identical. A moving magnet can inducean electric current in a wire, and an electric

current can produce magnetism in iron. Theconstruction of telegraph and telephone instru-ments depends on the fact that an electric cur-


rent can produce magnetism and that mag-netism can produce an electric current.We know effects which, we call "electricity",

just as we know the phenomena associatedwith living protoplasm without knowing what"life" is. It may be that "life" and "electricity",

as well as "electricity" and "magnetism", areall different aspects of the same thing.

Today we say, in the words of Dr. CharlesP. Steinmetz ("Relativity and Space", Pages18-19):—"The space surrounding a magnet is a mag-

netic field. If we electrify a piece of sealing-wax by rubbing it, it surrounds itself by adielectric or electrostatic field, and bodiessusceptible to electrostatic forces—such as light

pieces of paper—are attracted. The earth is sur-

rounded by a gravitational field, the lines of

gravitational force issuing radially from theearth. If a stone falls to the earth, it is dueto the stone's being in the gravitational field

of the earth and being acted upon by it."

Again:—"Suppose we have a permanent barmagnet and bring a piece of iron near it. It is

attracted, or moved; that is, a force is exertedon it. We bring a piece of copper near the mag-net, and nothing happens. We say that thespace surrounding the magnet is a magneticfield. A field, or field of force, we define as'a condition in space exerting a force on a bodysusceptible to this field'. Thus, a piece of

iron being magnetizable—that is, susceptible to

a magnetic field—will be acted upon; a piece of

copper, not being magnetizable, shows no ac-

tion To produce a field of force requires


energy, and this energy is stored in the spacewe call the field. Thus we can go further anddefine the field as

l

a condition of energy stor-

age in space exerting a force on a body suscepti-

ble to tliis energy'."

Thales said that the "divine moving power",the soul of nature, under certain conditions"moves iron", through the mysterious proper-ties of the lodestone. Modern science, borrow-ing from Aristotle the term energia, substitutesfor "soul of nature" the single word energy.Aristotle declared that "not capacity, but ener-

gy is the first principle anterior to andsuperior to anything else" (Metaphysics xii, 7:

cf. also Physics ii, 9, 6).

Modern science describes in more precisephrases what occurs when a body susceptible tothe influence of the magnet is brought intoproximity to a lodestone (magnetite). It givesus a picture of "lines of force" (energy) in adefined "field". But it tells us no more aboutwhat energy is than Thales tells us what his"moving power" is. Dr. Steinmetz tells us that"energy is the only real existing entity, theprimary conception, which exists for us be-cause our senses respond to it" (Op. cit.. Page23). For Thales the universal "moving power"of nature operates on or in all matter; for thephysicist of today the moving power (energy)is matter—man's perception of matter beingthe response of his senses to the vibrations ofenergy. "All sense perceptions are exclusivelyenergy effects," and "energy is the only realexisting entity."

Thales may or may not have considered the

;0 PRINCIPLES OP ELECTRICITY

cosmos as "matter" and "soul" or "movingpower". In any event the pre-Socratic Ionianphilosophers recognized no distinction betweenmatter and soul in our modern sense. Themoving power of nature (soul) was as mucha material substance as gross matter itself,

only more rarefied, more elusive. It was equiva-lent to the "energy"—electricity—of modernscience.

Here we have, then, the answer to the ques-tion: "What is electricity?" It is energy—"theonly real existing entity, the primary concep-tion, which exists for us because our senses re-

spond to it." "All sense perceptions are ex-

clusively energy effects." This is the answerto the question: "What are the Hertzian waves,used in 'wireless'?" It is the answer also to thequestion: "What is light?" as well as "What is

electricity?" By carrying the explanation of

the beam of light and the electromagnetic wave(like that of the radio communication station orthat surrounding a power transmission line)

back to the energy field (or, less accurately,the field of force), we have carried it back, asDr. Steinmetz well declared, as far as possible,

"to the fundamental or primary conceptions of

the hu»an mind, the perceptions of the senses."

All that we know of the world is derived fromthe perceptions of our senses, which are for usthe only real facts, all things else being con-

clusions from them; and "all sense perceptionsare exclusively energy effects." Electricity is

an energy effect, perceived by our senses. Noother definition or explanation can or needbe given, since energy is the primary conccp-

PRINCIPLES OF EDLECRICITY 11

Hon. And this explains also what matter i&,

since energy and matter are interchangeable

—

or equivalent—terms. What we call electricity*

is one of the \effects of energy on our senses-

In itself, it is energy, the stuff that matter is

made of; at once the "moving power" and thething moved.

Everything has been said that can be saidnow as to what electricity is: our concern inthe remainder of this volume will be to dis-

cover What electricity does and how it acts.

The reader of this little book who may oemore or less familiar with larger volumes deal-

ing with electricity, energy, electrons, electro-

magnetic waves or oscillations, magnetic anddielectric fields (usually combined), lightwaves,etc., will notice that no mention has been madeof the classical ether hypothesis, the universalplenum in which energy is said to be stored,and in which transverse waves of light aresaid to occur, ether atoms or vibrations mov-ing at right angles (perpendicularly) to thelight-beam.

Now, transverse waves can exist only inrigid (solid) bodies. The universal ether ofspace, referred to in the text-books, must—forreasons which I need not discuss here—be asolid body of a rigidity much greater than thatof steel, while at the same time possessinga very great elasticity so that bodies (suchas the planets) moving through it meet withno resistance, no friction. The electron theoryof Lorentz, Larmor, Thomson, Lodge and othersis based upon the assumption that such &


plenum, or medium, is a real substance. As amatter of fact, it is not known that any suchmedium (or ether) does exist, and it is now-recognized that while light is a uJave, a periodicphenomenon, like an alternating current, it is

not necessarily a wave motion of something orin something, any more than it is necessary to

assume the alternating current or voltage waveto be a motion of matter.

Electrical engineers make no assumption re-

garding the existence of an ether filiing all

space and interpenetrating all matter—have noneed for an ether as the hypothetical carrierof the electric wave. And just so the physicistof today has no real need for the classical as-

sumption that the light-wave is a wave motionof or in something of great rigidity yet highlyelastic and frictionless, filling all space. Lightis now known to be a high-frequency electro-

magnetic wave, and cannot logically be con-sidered as a wave motion of a hypotheticalether. "The ether thus vanishes, following thephlogistin and other antiquated conceptions.

"

2

As Prof. A. S. Eddington remarks in his "Re-port on the Relativity Theory of Gravitation"(1920), "Light does not cause electromagneticoscillations; it is the oscillations."

We know nothing whatever about the so-

2Steinmetz, Dr. Charles P., "Four Lectures onRelativity and Space," Pages 21-22, London andNew York. 1923, See Lecture II, "Conclusions from

Relativity Theory." Pages 12-45.Campbell, nan R., "Modern ElectricalTheory. Supplementary Chapters: Relativity,"

I r>idge University Press, 1923.


called ether of space; but we can formulatevery clearly "The Principles of Electricity"

without the aid of that hypothesise

CHAPTER 2

MAGNETIC PHENOMENA

It was long ago observed that if glass is

rubbed by silk, or a piece of sealing-wax or

hard rubber by fur or wool, an effect occurssimilar to that noted by Thales when amberis rubbed by similar materials—i. e., light bodiessuch as bits of dry paper, pith, etc., will cling

to the surface of the substance. After comingin contact with the attracting substance, thebits of paper, straw, etc., are then repelled.

If a ball made of pith be suspended at theend of a silk thread, and a glass rod whichhas just been rubbed with silk be brought close

to the ball, the pith-ball immediately flies tothe rod, clinging to it for a time. Then it jumpsaway, and instead of hanging vertically, seems

3Cf. Whittaker. E. T., "A History of the Theoriesof the Ether and Electricity from the Age of Des-

- to the Close of the Nineteenth Century,"Dublin and London, 1910. See also, Comstock andTroland, "The I tter and Electricity,"

I »r. Charles P., "Ele-mentary Lectui ctrie Discharges. Vand Impulses and Other Transierit York,1914; and Starling, Dr. Sydney G., "Electricity,"London and New York, 1922.


to be pushed away from the glass by a mys-terious force. A second ball, treated like thefirst, and brought near the first, is violently re-

pelled. But if one ball is charged from theglass and one from tho wax, they attract in-

stead of repelling each other. Two pieces of

glass or two pieces of wax'repel each other.

A similar attraction and repulsion was early

observed between the poles of the magnet. Thisinfluence seems to be transmitted by some in-

visible agency or medium across the interven-ing space between the bodies, and in this re-

spect the force does not differ from that actingbetween the moon and the earth, or the earthand the sun. And just so, if a light piece of ironis placed near a magnet, it moves to the mag-net and clings to it; but if the magnet is thelighter of the two bodies, it moves toward thepiece of iron.

Although Thales had attempted to explain thecause or nature of magnetic attraction as longago as the end of the seventh century B. C,or in the first quarter of the sixth century(about 2,500 years ago), it was not until theyear 1582 A. D. that Dr. William Gilbert (1540-

1603), of Colchester, physician to Queen Eliza-

beth, made the first experimental study of mag-netic phenomena. It is to Dr. Gilbert that weowe the name electricity as applied to this

force, derived from his vis electrica.

By 1600, Dr. Gilbert had published hisepochal work "De Magnete", which not onlycontained the first rational treatment of mag-


netic and electrical phenomena, but was alsovirtually the first scientific work published in

England. It is to this truly great treatise thatmust be traced the beginnings of the science of

electricity.

^

Throwing aside, as useless, mere philosophi-cal speculation as to the nature of magnets,Gilbert explained in his book how practicalexperiments should be carried out. He insistedthat it is to nature herself that we must ap-ply for the answers to problems in "naturalhistory". Gilbert's particular objective was not,

however, discovery of the laws of magnetismor electricity; what he most desired to learnwas the composition of the earth: he wishedto know through actual research just what is

its innermost constitution. His experiments ledhim to the conclusion that the earth is a mag-net. It may, indeed, be considered a hugespheroidal lodestone.

Gilbert told his readers to take a piece oflodestone (natural magnetic iron) of conven-ient size, turn it on a lathe to the form of aball, then place on the terella (as he called

the spherical lodestone) a piece of iron wire. It

40n the Continent, experimental work in otherfields was already in progress, thanks to thegenius of Descartes, Galileo and other founders of

ii science. Gilbert, like Harvey, spent someyears in Italy, coming under the direct influence ofthe great Italian phvsiHst-astronomer-physicianGalileo. Harvey was in Padua (159 8-1602) duringGalileo's professoriate. The introduction of scien-tific methods in England at this time may well becredited to Italian and French influences.


will then be observed that the ends of the wire"move round its middle point."s

Lodestones, fragments of magnetite (Fe3o4 ),

are said to have been first discovered at Mag-nesia, in Asia Minor,—hence the word mag-netism. Some of the earliest references to thelodestone relate to its property of lying in anorth-and-south direction when an elongatestone is freely suspended, one particular end al-

ways pointing northward, just as the great mag-net the earth, or the mariner's compass-needle,has two opposite magnetic poles. The locationof the poles of a disk-shaped stone is readilyfound by turning it round in the presence of acompass-needle.6

Iron and steel are more strongly magneticthan any other metals. While only one kind of

iron ore is naturally magnetic—forming mag-nets—the property of magnetism may alwaysbe given to any kind of iron or steel. One needonly strike an iron bar while it is lying in anorth-south position, or rub the iron with a

magnet, and it becomes a magnet. If it is

desired to make a permanent magnet, steel mustbe employed. A compass-needle is thereforemade of magnetized steel. If balanced upon apivot, the positive pole of the needle will point

^Gilbert's book is usually referred to simply as"The Magnet," but the full title is : "Concerningthe Magnet and Magnetic Bodies, and Concerningthe Great Magnet the Earth : A New Natural His-tory (Physiologia) Demonstrated by Many Argu-ments and Experiments."

^Magnetite does not always possess polarity. Itis called "lodestone" only when it does. It occursnot only in the form of more or less massive stones,but also as loose sand and in earthy forms.


(roughly) towards the earth's north geo-

graphical pole. 7

A compass-needle is also a "dipping needle",unless the suspended magnetized needle lies

about half way between the earth's magneticpoles. The north magnetic pole lies below theearth's surface—at an unknown depth—at theextreme northeastern corner of the continent of

North America; and the corresponding southmagnetic pole on the edge of the Antarctic con-tinent—King George's Land—about 2,300 milessouth of Australia. These magnetic poles donot correspond even roughly with the geo-graphic poles, nor does the magnetic equator byany means correspond with the geographicequator.

Only a small section of the magnetic equatorruns north of the true (geographic) equator

—

e. g., from the coast of Brazil to the coast ofKamerun (Africa).

According to Prof. T. J. J. See, "the wholemagnetic system has been pushed southward200 miles by bodily displacement of both polestowards the ocean hemisphere." This eminentphysicist-astronomer also stated (in 1922) thathis researches led him to the discovery that thetwo magnetic poles are at unequal depths inthe earth, the North Pole being much deeperthan the South Pole, "with the result that thetotal magnetic forces in the southern hem-

"The fact that a lodestone possesses two "poles"was discovered in the thirteenth century by PetrusPeregrinus, of Picardy, while he was experiment-ing with a spherical lodestone and a needle.

18 PRINCIPLES OP ELECTRICITY

isphere are considerably stronger than in thenorthern hemisphere."8

It was long ago discovered that if one startsnorthward from the magnetic equator, thecompass-needle soon begins to dip downward(and northward). At the southern border of

the United States, the downward inclinationamounts to about 57 degrees. At the borders ofNorth Dakota and Maine the dip is about 76degrees. By the time Hudson Bay is reachedthe needle assumes a vertical position. Thismeans that it is here suspended immediatelyover the north magnetic pole itself. At the mag-netic equator in Peru, a needle suspended bya thread is exactly balanced. Dr. See states

that at the North and South Poles there is adownward pull—by the magnetic force—of just

one millionth of the gravitational force, whilein Peru the total magnetic force is preciselyone ten millionths of gravitation.

It has been found that both the North andthe South Poles are anything but fixed in po-

sition. They "wander about in their subter-ranean region". In the course of centuries, the

8From notes taken at a lecture by Dr. See beforethe California Academy of Sciences in 1922. Dr.See, in charge of the United States Naval Observa-tory at Mare Island (California), presented in thelecture "A New Theory of the Ether," in which heoutlined the grounds upon which he based his newtheory of a direct connection between magnetismand universal gravitation. It is highly interesting,in this connection, to learn that Dr. Albert Einstein,in collaboration with Professor Eddington (of Cam-bridge)—working on the principle of Relativity

—

,

has discovered a connection between the earth'spower of attraction (gravitation) and electricity.

PRINCIPLES OP ELECTRICITY 19

compass-needle swings from west of north, andthen to the east. Even the amount of the dipslowly changes, in a periodic way, and at everypoint'on the earth. For example, in 1576, thenorth end of the needle at London dipped at

an angle of 71 degrees 50 minutes. By 1720the angle had increased to 74 degrees 42 minutes—almost up and down. Since then, the dip at

London has continually decreased. At the pres-

ent time we are puzzled by the fact that theinclination of the dip is 66% degrees at Londonand more than 70 degrees at Washington.

It has long been known that variations in

magnetic declination of the delicately mountedneedles, in observatories, are directly corre-

lated with solar disturbances. The late Dr. A.Wolfer (sometime director of the Zurich Ob-servatory) was the first to show us how close-

ly the curve of the sun-spot activity rises andfalls with the fluctuations of magnetic de-

clinations.Before attempting to explain the peculiarities

of magnetic action in terms of the modern elec-

tromagnetic theory, it will be well to recallcertain stages of progress in the development ofthis theory. This plan will permit elucidationof the theory itself by "easy steps".

CHAPTER 3

PIONEERS IN ELECTROMAGNETIC THEORYThe Danish physicist, Hans Christian orsted,

professor of natural philosophy at the Univer-sity of Copenhagen, showed us, more than acentury ago, that a magnetic needle can bedeflected by an electric current. He had been


led by theoretical considerations to assume thatthere must be a correlation between electric

and magnetic forces. While yet a young man,orsted endeavored by persevering experi-mentation to prove the correctness of his theory.While he did not expect a parallel action of thetwo forces, he "was firmly convinced that mag-netism and electricity were inseparable twins.

He noted that both heat and light radiatedfrom a conductor when heated to incandescence.He also assumed that magnetic forces are radi-

ated from a conductor traversed by electricity.

In 1820, while lecturing before his class, hebecame convinced that the apparatus he wasthen using could be made to demonstrate thecorrectness of his views. He asked his pupils to

accompany him to his laboratory, where, as hepredicted, a slight deflection of the magneticneedle, turned at right angles to the electric

current, was shown when placed close to thecopper wire. Some months afterwards, witha stronger current (made up of twenty cells),

he obtained much more intense effects. Investi-

gating these in detail, he found that they metall the requirements of his theory. So, on July21, 1820, he sent out. to the scientific world hisnow famous circular, "Experimenta circa ef-

fectual conflictus electrici in acum magneti-cum" (Experiments on the effect of the electri-

cal conflict in the magnetic needle).

orsted showed, furthermore, how changes inthe position of the magnetic needle occurredwith variation of the position of the conductor(copper wire) in regard to it. He demonstratedalso that the magnetic effect was not weakened


by insulators—chat it would penetrate variousmaterials, whether these were conductors ofelectric currents or not. He showed that themagnetic field created by the electric currentdoes not have any influence on a needle of non-magnetic material— i. e., brass, glass, etc. It is,

in fact, chiefly in the fact that it cannot be in-

sulated that magnetism differs from electricity.

It will freely pass through air, stone, mica,glass, clay, brick, or any insulating material.

It is well wrorthy of especial mention thatorsted employed the term "conflictus" to

designate the electric current, many decadesbefore the origin of the electron theory of mat-ter. For, on modern theories of electricity, it

is the movement to and fro of electric particles(electrons) through the conductor, and theirimpact ("conflietus") that produces what wecall electrical phenomena.

orsted's fundamental discovery of the mu-tual effects between electricity and magnetismled to further discoveries which made possiblethe construction of telegraph and telephone in-

struments, since these depend on the fact thatan electric current can produce magnetism,and that magnetism can produce an electriccurrent.

If we wind around an iron bar a numberof turns of insulated wire, and an electric cur-rent is allowed to pass through the coil, thebar becomes a strong electromagnet. But it re-

mains a magnet only as long as the current is

passing. Now, the magnetic effects obtainedwith the electromagnet are identical with thoseobtained from a permanent magnet—such as


the familiar horseshoe magnet, commonly seenon the flywheel of the Ford automobile, or inthe ordinary telephone generator for calling up"Central". In the case of a telegraph instru-ment, it is important that the iron is a tem-porary magnet. On the other hand, a permanentmagnet is an essential part of every Bell tele-

phone receiver. This permanency is secured byemploying a bar of steel instead of a piece ofiron—a temporary magnet.

The power produced from a dynamo—or elec-

tric generator—depends upon the fact thatwhen a magnet is put into a coil of wire, onlya momentary current of electricity passesthrough the wire, in one direction. If the mag-net is withdrawn, a current starts in the op-

posite direction. Copper wire coiled about aniron core forms the "armature" of the dynamo.The rotating coils are said to "cut the mag-netic field." On this principle of electricity,

intense electric currents are produced, furnish-ing the "power" for the electric motors in elec-

tric cars, elevators, musical instruments, etc.,

and for electric lights—incandescent and arc.

Dynamos may contain either permanent mag-nets or electromagnets. They produce the mag-netic field in which the "armature" or con-

ductor—the coils of wire wound around theiron core—rotates. A machine with permanentmagnets is usually termed a magneto, and is

never made in large sizes. The current for theelectromagnets may be derived wholly from anoutside source, or part of the current whichit generates may be used for that purpoae.


The current generated in the armature windingis alternating, but may be rectified to a direct

current by a commuter if desired; otherwiseit is conveyed to the line circuit by collector orslip rings and brushes.

We owe much of our knowledge of magnetismand electricity to Michael Faraday (1791-1867),who brilliantly covered the whole field of thesesciences. Faraday was distinguished alike as achemist and as an experimenter in electricity

and magnetism.

orsted had shown that magnetism could beproduced by a current of electricity, but it re-

mained for Faraday to produce current elec-

tricity by a magnetic "field of force", thus lay-

ing the foundation for those modern industrieswhich derived motive force for their machineryfrom the gigantic dynamos of our "powerhouses".

But I must here introduce a few facts con-cerning the contributions to electric theory andpractice of the great French mathematician andphysicist, Andre Marie Ampere (1775-1836). Hisdiscoveries in electrodynamics aided greatlyin laying a broad foundation for this science.Very notable was the influence exercised byAmpere on the development of electro-dynamics.And it was he who first clearly established thefact that magnetic action is a peculiar formof electromotive action, and that, in phenomenaof this class, "action and reaction are equaland opposite."From these considerations it was natural for

him to suppose that magnetism might be madeto produce electricity, as it had already been


shown that electricity might be made to imi-tate all the effects of magnetism. Numerousattempts were made to effect this predictedresult, but for some years all such effortsproved to be fruitless.

Meanwhile the French physicist and astrono-mer, Frangois Arago (1785-1853), was also con-ducting experiments with the object of produc-ing electricity by magnetism. One of his ex-periments actually involved the effect sought,but it was not clearly recognized. Arago ob-

served that the rapid revolution of a conduct-ing plate in the neighborhod of a magnet gaverise to a force acting on the magnet. But it

was not recognized by either Arago or otherphysicists of the day that the forces involvedwere electric currents—produced by the rapidlyrevolving conducting plate.

Faraday, in 1831, after several years of pre-

occupation with other problems, returned to his

task of discovering electrodynamical induction,begun in 1825. After a number of fruitless ef-

forts, he /was finally rewarded with success,

but not in the form which had been anticipated.It was observed that at the precise time ofmaking or breaking the contact which closedthe galvanic circuit, a momentary effect was in-

duced in a neighboring wire, which, however,disappeared instantly.9

Faraday then discovered that a similar effect

could be indue d merely by moving the wirenearer to or farther away from the closed cir-

cuit—instead of suddenly making or breaking

9Philosophical Transactions, Page 127. 1832;First Series, Article 10.


the contact of,the "inducing circuit". Later hefound that the effects were increased by theproximity of soft iron, and that when the soft

iron was affected by on ordinary magnet in-

stead of the voltaic wire, the same effect still

recurred. The momentary electric current wasproduced either by moving the magnet or bymoving the wire with reference to the magnet.Finally, it was found that the* earth itself mightbe substituted for a magnet, not only in this ex-

periment but also in others. Mere motion of awire, under proper conditions, produced the ef-

fect.

Here, then, was the true explanation of

Arago's experiment: by the rapid revolution ofthe plate the momentary effect became continu-ous. Without using the magnet, a revolvingplate became an electrical machine. A revolvingglobe was found to exhibit electro-magnetic ac-

tion, the circuit being complete in the globeitself without the addition of any wire. It waslater found by Faraday that mere motion of thewire of a galvanometer produced an electro-

dynamic effect upon the needle. 10

Meanwhile, Ampere, "by a combination ofmathematical skill and experimental ingenuity,first proved that two electric currents act on

loOne of the first electrical experimenters to de-vise the instrument known as a "galvanometer" was

igger, of Halle. There are noweight or more varieties of this instrument (or ap-paratus) in use. It enables the Investigator to

re extremely minute electrodynamic actions,or the very weakest intensity

1

of an electric cur-rent, as well as to detect its presence or direction,usually by the deflection of a magnetic needle.


one another, and then analyzed this action intothe resultant of a system of push-and-pull forcesbetween the elementary parts of these cur-

rents."11

orsted having shown that electric currentsproduced certain effects on magnets withoutbeing in actual contact, and Ampere havingdemonstrated that magnets can in their turnbe supplemented by electric currents,—a mag-netic needle being deflected not only by a cur-rent passing through a wire, but also by an-other magnet brought into its neighborhood,and two electric currents acting on one an-other at a distance—the question now arose asto whether or not electrical attraction and re-

pulsion could be reduced to an action at a dis-

tance proportional to the inverse square of thedistance.

As early as 1773, Henry Cavendish (1731-

1810)—one of the foremost chemists and ex-

perimentalists of his day—answered this ques-tion affirmatively by experiment. 12 Coulomb(1736-1806)—inventor of the torsion balance

—

UMaxwell, Clerk, "On Action at a Distance,"(Scientific Papers, Vol. II, Page 317).i2The scientific papers of Cavendish were pub-

lished (in 1879) under the title, "The ElectricalResearches of the Hon. Henry Cavendish," editedby Clerk Maxwell. Cavendish anticipated manylater investigations of British and Continentalwriters, including Ohm's law— i. e., the propor-tionality between the electromotive force and thecurrent In the same conductor; and anticipated alsoFaraday's discovery of the specific inductive ca-pacity of different substances, even measuring its

numerical value in several substances. He had alsoarrived at the conceptions of electrical capacity andof "potential."

PRINCIPLES OF ELECTRICITY 2?

showed that ponderable matter charged with,

electricity followed the same formula for at-

traction and repulsion as gravitating bodies did.

Poisson (1781-1840) worked out the difficult

mathematics of fluids actuated by repellingforces depending on the inverse square of thedistance. Laplace (1749-1827) had very earlybecome convinced that the actions of ponderablesubstances in which electric currents wereflowing could be reduced to an action at a dis-

tance proportional to the inverse square of theelements of the electric current.

Faraday regarded the electric field as full

of lines of electric force, in a state of tension,and naturally repelling each other. To him,as to a number of his contemporaries, the ideaof "action at a distance" was repugnant; thoughsuch a possibility seemed to be indicated bythe action of gravitation—the relation of theforces between two charged bodies to the dis-

tance between them being very similar to thatof the gravitational forces between two bodiesto the distance between them. But Faraday,like^the great Descartes long before him, re-

jected the theory of action at a distance infavor of "action through a medium."Ampere had sought for some sort of me-

chanism for the transmission of electromag-netic currents. His own discoveries and thoseof orsted led him to formulate the hypothesisthat 'the field in the vicinity of a magneticbody is produced by a number of exceedinglysmall circular currents which flow undampedin or around the molecules and that magnetiz-ation consists merely of the bringing of t&ese


molecular currents into a parallel direction.But it was difficult for some physicists, evenin Ampere's day, to accept the hypothesis ofundiminished currents possessing no resist-

ance.

If we transform the idea of the "molecularcurrents" of Ampere into the language of to-

day, substituting for these molecular currentselectrons revolving in atoms, it can be shownthat the great French scientist was substantial-ly correct in his assumptions. In 1915 Dr. Al-bert Einstein and W. J. de Haas astonishedthe world of physicists by showing experi-mentally—by means of a most ingenious ap-paratus—that the "molecular currents" or re-

volving electrons really exist.

In 1919, Professor Kramerlingh-Onnes, at theUniversity of Leyden, was able to produce whathe called imitations of ampere currents—i. e.,

"undiminished currents producing no resist-

ance." It was demonstrated that the resistanceof pure gold and pure platinum differ verylittle if at all from nil at low temperatures.But wires of these metals, of absolute purity,are difficult to obtain, so mercury was selectedfor the experiments. The resistance of themetal at the lowest attainable temperature of

liquefied helium, -271.5° C, (at a pressure of

3 mm. of the mercury column), proved to beimmeasurably small. The resistance down to

a position shortly below 4.2° K. (Kelvin's ab-

solute scale) suddenly dropped from a measur-able amount to a value practically nil. It wasfound that the induced current remained in astate of circulation, and that the decrease in


the strength of the current amounted to less

than 1 per cent per hour, from which it fol-

lowed that the "time of relaxation" mustamount to more than four days!*-At the absolute zero of temperature, it is

supposed that the orbits of electrons in atomsare perfect circles, whatever their paths maybe at measurable temperatures. This motionof the electrons remains when all heat hasdisappeared, since it is not this motion of therevolution of the electrons in their orbits thatis associated with the energy of heat. Heat is

a mode of motion of the atoms themselves,not of their contained electrons; though in-

crease of heat doubtless results in an increasein the average orbital velocity of the electrons.

Since Ampere's day we have learned at all

events, that an electric current means the flowof electrons, either from atom to atom, orpassing between the atoms, along conductors.In 1920, Lord Kelvin came to the conclusionthat at the absolute zero resistance of metalsmust be infinitely great, the degrees of dis-

sociation of the electron being, he supposed, nil

at the zero hour. If any free electrons re-

mained, he believed they would lose their powerof motion, condensing like a vapor upon themetal atoms and freezing fast to them (toborrow a phrase from Kamerlingh-Onnes). Theexperiments of the c lebrated Holland physicistshow that the resistance of metals decreaseswith lowering of temperature, and would prob-ably become nil at the absolute zero with em-

l3See Die Naturivissenschaften (Berlin), January18. 1921.


ployment of a perfectly pure platinum wire. If

this is true, then would a current of electricity,

once set up in a conductor, continue forever?

CHAPTER 4

THEORIES OF ELECTRICITYThe science of electricity is based upon ob-

servation of those phenomena of attractionand repulsion which are comprehended underthe term electrostatics. Statical electricity, sonamed from a Greek word (statikos), whichmeans "causing to stand (or stay),"—also

called frictional electricity—is the electricity

of stationary charges caused by rubbing to-

gether unlike bodies, such as glass and silk

(noted in Chapter II). In such cases equaland opposite charges of electricity are alwaysproduced. The term statical electricity appliesproperly, however, to the electricity of all sta-

tionary charges, however produced.The electricity upon the surface of glass is

called positive electricity; that upon rubber,negative electricity. When silk is rubbed uponglass it receives a negative charge from theglass and confers a positive charge upon thesilk. Wool or fur rubbed on wax or rubberreceives a positive charge in exchange for anegative charg . "equal and opposite chargesof electricity are always produced." A piece

of glass and a piece of silk attract one another;two pieces of silk or two pieces of glass orwax repel one another, because a body which is

positively charged is attracted by one nega-tively charged and repelled by one negativelycharged, and vice versa. A piece of glass


rubbed by a piece of silk, under suitable condi-

tions, attracts any other body with which it

has not been in contact. The piece of silk will

do likewise. In all these cases, the attractionor repulsion becomes weaker with increase of

distance between the attracting and repellingbodies.

A third body which has been in contact witha piece of glass or a piece of silk acquires to

some extent the pr perties of the glass or silk

with which the third body has been in contact.And, conversely, the glass or silk with whichthe third body has been in contact attracts orrepels with less force than before. If a handis drawn over the surface of an object afterit has been charged with electricity, the elec-

tricity disappears. It has been conductedthrough the hand and the body to the earth.This phenomenon shows that the human bodyis a conductor of electricity. But most metalsare much better conductors. Moist air anddamp wood are rather poor conductors, whiledry air, dry wood, porcelain, glass, hard rubberand sealing-wax are non-conductors, or insula-tors.

The term dielectric is used in preference toinsulation when reference is made to the prop-erty of transmitting induction—a process quitedistinct from ordinary transmission of an elec-

tric current. In electrostatic induction, a bodyelectrostatically charged induces in a neighbor-ing conductor a like charge in the parts farthestfrom the charged body, and an unlike charge inthe nearer parts; the repelled like charge be-ing removed by connecting any part of the


conductor momentarily with the earth, whilethe bound unlike charge spreads over the wholesurface of the conductor and remains thereeven when the inducing body is moved away,or its charge neutralized, if the conductor is

properly insulated.Dielectric strength refers to the ability of an

insulating material to resist rupture by highvoltage, measured by the voltage necessary to

effect a disruptive discharge through it. In-

sulation resistance, on the other hand, refersto the ohmic resistance offered by an insulatingmaterial to an impressed voltage, tending to

induce a breakage of current through it. Theterm dielectric is used as a synonym for in-

sulator, in the sense that a charge on one partof a non-conductor is not communicated to anyother part. A charge given to a conductorspreads to all parts of the body. A dielectric

possesses the property of transmitting electric

force by induction but not by conduction. Acharge on one part of a non-conductor or di-

electric is not communicated to any other part.

Jeans suggests that since the presence of

magnetic energy is always associated withcharges in motion, whereas electrostatic energyis present when all the charges are at rest

relatively to each other, it may be proper to

identify electrostatic energy with potentialenergy, and magnetic energy with kinetic en-

ergy^— i. e., energy due to motion of particles,

rather than to energy of position, as of a coiled

spring.

i4Jeans, J. H., "Electricity and Magnetism,"Page 483, 1911.


Statical energy is distinguished from "cur-rent electricity" by the fact that it accumulateson various bodies—is stored up—and as soonas proper connections are made, it dischargesinstantly. Statical electricity is used by physi-cians in electrical treatment of diseases andin X-ray work. Machines have been constructedthat will produce very strong charges of stati-

cal electricity.

If a sufficiently large charge of electricityaccumulates upon an insulated conductor inan electrical machine, it finally discharges it-

self, passing through the air to the nearestbody. A flash of lightning is the result of anovercharge of statical electricity accumulatedupon cloud particles, and may pass from cloudto cloud or descend to the earth.18 Carefuldrivers of gasoline-tank wagons allow an ironor steel chain to drag on the roadway from ametallic connection, which conducts any sur-plus "static" to the ground. Failure to providefor such an emergency sometimes results in aterrific explosion with consequent loss of life.

About the beginning of the nineteenth cen-tury, the Italian scientist, Alessandro Volta(1745-1827),—and other physicists—discoveredwhat has been called, after Volta, voltaic elec-

tricity, a current generated by chemical actionbetween metals and different liquids as ar-

ranged in a voltaic battery. The term "volt"

—

ihe electromotive force which performs workat the rate of one joule per second (one watt)

lSBeniamin Franklin was first to show (in a let-llinson, written October 19.

that lightning and electricity are one and th<thinfj He was also inventor of the lightning-rod.

*4 PRINCIPLES OF ELECTRICITY

in producing a current of one ampere—wassimilarly derived.

It was learned that if two different metals,such as copper and zinc amalgam, are placedin a weak acid solution (such as one part H 2S04

to four parts H20), and connected by a wirefastened securely to the metals, a current ofelectricity (about two volts) will pass throughthe wire. Carbon (a non-metal) and a metalupon which the solution acts chemically maybe used instead of two metals. There must bechemical action between the liquid and onemetal, or there will be no current. Such acombination constitutes a cell, and two or morecells make a battery. The current starts withthe zinc, is conducted by the solution to thecopper, and thence by wire back to the zinc,

completing a circuit. The zinc constitutes thenegative pole (or electrode), the copper or car-

bon the positive pole (or electrgde).

A cell frequently employed, where a weak(about 1.1 volts) but constant electromotiveforce ("E. M. F.") is required, is one devisedby the English physicist, John D. Daniell (1790-

1845). In this cell a copper sulphate solutioncontaining a copper electrode is placed in con-

tact (by means of a porous wall or partition

—

usually an unglazed porcelain cup) with a zinc

sulphate solution containing a zinc electrode.

The zinc electrode is negative to the copper.At each electrode there exists a potential dif-

ference between solution and electrode. 1G The

i6"Potential" is analogous to level (or pres-sure) in hydrostatics or mechanics.


two electrodes being connected externally bya wire, a current of electricity will flow through,the wire from the copper to the zinc, and zincwill dissolve at the anode (positive pole) andcopper deposited on the cathode (negativepole). The current in this case, as in the pre-

ceding, is said to be produced by voltaic actionand the cell is a primary battery. Voltaic ac-

tion and electrolysis—the process of chemicaldecomposition (or dissociation of compoundsor molecules)—by the action of an electric cur-

rent produced externally (as by a dynamo) andforced through the cell, are essentially identicalphenomena, and obey the same laws. 17

i The familiar dry cell contains no liquid whichmight be spilled, and is very useful for certainpurposes, as in automobiles, and in operatingdoor-bells. It is merely a voltaic cell whosechemical contents are made practically solid(or paste-like) by the use of some absorbent,as gelatine, sawdust, etc. In cells of theLeclanche type, a mixture of plaster of Paris,flour, and sal ammoniac takes the place of thesolution which acts chemically upon one ofthe contained metals. When used up, a drycell must be replaced by an entirely new cell.

Two or more dry cells constitute a dry bat-tery.

We have seen that there are two typesof charged bodies, of which charged glass andcharged silk are familiar examples. It wasDufay (1699-1739) who discovered that there

HFor further explanation, see Shipley, Maynard,"The A. B. C. of the Electronic Theory of Matter,"Little Blue Book Series, No. 603.


were two kinds of electricity, one of whichhe called vitreous (from glass) and the otherresinous (from resin—amber). The terms"positive" and "negative" in relation to elec-tricity were first applied by Benjamin Frank-lin, in 1756. To the electricity of the glass rodFranklin gave the name "positive" and to thatof the sealing-wax (or hard rubber, amber,etc.) the name "negative." These names arenow universally in use—though French physi-cists still speak of vitreous and resinous elec-

tricity.

I have spoken also of a positive pole (orelectrode) and a negative pole (or electrode).The electrodes constituting the two poles of acurrent are also called the anode and thecathode, the former being the positive elec-

trode and the latter the negative electrode. 18

When it was learned that electrical chargescould be distinguished by two opposing terms—positive and negative—it was natural to sup-pose that there were two distinct kinds ofelectricity, or "fluids." This was the viewtaken by the French chemist Dufay. But theGerman electrician JEpinus (1724-1802), in his

great pioneer work, "Tentamen Theoriae Elec-tricians et Magnet ism i" (An Attempt at aTheory of Electricity and Magnetism—1759),considered the mathematical consequences ofthe hypothesis of a single fluid, attracting all

matter but repelling itself. It soon becameapparent, however, that he must assume either

the existence of two electrical fluids or the

i8See, in this connection, Shipley, Op. cit.


mutual repulsion of material particles. Hechose the latter theory. He explained thephenomena of the opposite poles as results of

the excess and deficiency of a "magnetic fluid,"

which was dislodged and accumulated in theends of the body, by the repulsion of its ownparticles, and by the attraction of iron andsteel, as in the case of induced electricity. 19

iEpinus, who was unquestionably one of thegreatest physicists of the eighteenth century,devised a method of examining the nature of

the electricity at any part of the surface of abody, by which mer.ns he was enabled to ascer-

tain its distribution. He found that the dis-

tribution was in agreement with the attractionsand repulsions which objects exert when theyare in the neighborhood—"electrical atmos-phere"—of electrified bodies. Today we saythat such bodies are electrified by induction.

The yEpinian theory of electricity and ofmagnetism was modified and presented in anew form (in 1788) by Coulomb, with two fluids

instead of one. His first task, before reducingthe theory to calculation, was to determinethe law of the forces involved—not being satis-

fied, for example, with Newton's assumptionthat the attractive force of magnetism is in-

versely to the cube of the distance. Mayer in

1760, and Lambert a few years later, hadfound the law to be that of the inverse square.Coulomb desired experimental confirmation ofthis law before accepting it as established.

39A very similar hypothesis was read before theRoyal Society by Henry Cavendish, in 1771, thework of ^Epinus being unknown to him at the time.


This he secured by means of his torsion-balanee

(about 1784).20

It was in pursuance of this investigation thatCoulomb brought to light for the first time thefact that the directive magnetic forces whichthe earth exerts upon a needle is a constantquantity, parallel to the magnetic meridian,and passing through the same point of theneedle whatever be its position.

Barlow, who had adopted the two-fluid hy-pothesis, showed that the magnetic "fluids"were collected at the surface of spheres (of

iron), the surface being the only part in whichthere could be detected any magnetism. Hedemonstrated that a shell of iron produces thesame effect as a solid ball of the same diam-eter. Poisson's later analysis (1824) showedthat this was a consequent to be expected.Merz has well said that what Laplace did forNewton was done by Poisson (1781-1840) "for

Coulomb's elementary law of electric and mag-netic action, and on a still larger scale byGauss, who worked out the mathematical theoryand applied it to the case of the magneticdistribution on the earth's surface. In Eng-land, already before Coulomb's researches werepublished, Cavendish had, likewise by a com-bination of experiment and calculation, es-

20By means of this instrument very minute forcescan be accurately measured, such as electrostaticor magnetic attraction and repulsion, by the torsion(turning or twisting) of a wire or filament, theangle of torsion being proportional to the amountof force exerted.


tablished the elementary formulae and proper-ties of electrical phenomena."- 1

Benjamin Franklin, the first American togain international renown as a scientist, adopt-ed and developed a "one fluid theory of elec-

tricity." On this supposition the parts of thefluid repel each other, and the excess in onesurface of the glass—for example—repels thefluid from the other surface. The fluid itself

was regarded by Franklin as positive, the partof the other (negative electricity) being takenby ordinary matter, the particles of which weresupposed to repel each other and attract thepositive fluid, just as the particles of the nega-tive fluid did on the two-fluid theory.On both the two-fluid and the one-fluid

theories, as we have seen, the particles of thepositive fluid repelled each other by forcesvarying inversely as the square of the distancebetween them—as shown by both .^Epinus andCoulomb. This is true also of the particles ofthe negative fluid. The particles of the posi-tive fluid attracted those of the negative fluid.

In Franklin's one-fluid theory it was the or-dinary particles of matter which attracted thepositive fluid and repelled one another. Boththeories from their very nature imply, as SirJ. J. Thomson long ago (1906) pointed out, theidea of action at a distance.

In his very interesting book, "Matter andEnergy" (1912), Professor Soddy says: "Allelectrical phenomena can be explained as wellon the one-fluid as on the two-fluid idea, but

21Merz, Henry. "History of European Thought inthe Nineteenth Century," VoL I, Page 362.


our ignorance at the present time as to whetherthere are two kinds of electricity or one is

fundamental. Until the question is settled,

the hopes that have been entertained that,

through the study of electricity, we shall beable to arrive at a philosophical explanationof matter, are likely to prove unfounded."

Our modern view of electrification bears aclose resemblance to the one-fluid theory ofFranklin, whether we suppose there is onekind of electricity, or two kinds. At all events,if there be such a separate force, or such unitsof energy, as "positive" electricity, it has neverbeen isolated, as have been the negative atomsor electrons. Negative electrification is but acollection of these negative corpuscles or unitcharges. The particles of the "electric fluid"

of Franklin correspond to these electrons.

"Instead of taking, as Franklin did, the elec-

tric fluid to be positive electricity, we take it

to be negative," says J. J. Thomson, in his"Corpuscular Theory of Matter" (1906). And"the transference of electrification from oneplace to another is effected by this motion ofcorpuscles from the place where there is a gainof positive electrification to the place wherethere is a gain of negative. A positively elec-

trified body is one that has lost some of its

corpuscles."22

22For a recent work on modern electrical theory,see Starling, Sydney G., (head of the departmentof physics in the West Ham Municipal College,London), "Electricity," London, 1922. For thepioneer work of Ampere, see his "Theorie des Phe-nomenes Electrodynamiques," 182S.

JraiNCIPLES OF ELECTRICITY 41

CHAPTER 5

MODERN MAGNETIC THEORYWe have already shown how the magnetism

of a magnet is converted into electricity, bymeans of rotating coils cutting the lines ofmagnetic force in the "field." The energy usedto drive the machinery may, of course, be de-rived either from water-power or by steam.Gravity gives energy to falling water; chemi*cal energy produced by the oxidation of coalbecomes heat energy, which in turn causes theexpansion of steam, which produces energy ofmotion in a piston; and this motion, trans-mitted to the parts of an engine to a dynamo,produces electrical energy. When the electriccurrent from the dynamo has been conductedto any desired point by cables, another motor,acting in the opposite sense, causes the elec-

tricity to change back again into the originalmechanical energy, less the loss due to im-perfections in the operation. Here we have,then a clear picture of what is meant by thephrase, transformation of energy.

But another question naturally arises at thispoint. We know that with a finite quantityof magnetism we can produce an unlimitedquantity of electricity. Yet we add no newmaterial, no source of supply, to the dynamo.Let the rotating coils continue to cut the linesof magnetic force in the magnetic field, andthe magnetism of the magnet will be trans-formed into current electricity—furnishing aliterally exhaustless supply from the greatstorehouse of nature. For us the energy of the


universe is infinite in quantity. The reservoirof energy is exhaustless, and the dynamo is

man's open sesame.But just here the very interesting question

arises: Is the inexhaustible supply of electric

current with the expenditure of a limited quan-tity of magnetism fully explained by sayingthat it is due to the rotational movement ofthe coil? Can the mere rotation of a metalin a magnetic field actually create an endlesssupply of available energy? Not likely! AsDr. Gustave Le Bon well says: "Such ametamorphosis would be as marvelous as trans-formation of lead into gold by simply shakingit in a bottle. Another interpretation must besought for the phenomenon.

"

Now, a current of electricity is known to bea stream of electrons (negative charges) flow-ing along or in a conductor; and an electron is

an atom of

—

energy. But where was this

energy stored? "In the all-pervasive ether,"say many physicists. "There is no ether," sayothers. The electromagnetic field representsenergy storage in space—not in a universal,incomprehensible, paradoxical something called"ether."A field of energy is intelligible. It takes the

place of the conception of action at a distanceand of the ether. No "ether" need be postu-lated as the carrier of the field energy in space.It is its own carrier. "Energy is the only realexisting entity, the primary conception, whichexists for us because our senses respond to it"

(Steinmetz)."Lines of force," says Dr. N. R. Campbell,

PRINCIPLES OF ELECTRICITY 4m

the famous English physicist, "are just linesof force, independent for their existence of aUsurrounding bodies, and there is no more to besaid about them. . . . Our Electrical theory,so far from providing additional support forthe conception of the ether filling all space,does not require such a conception at all."

Dr. Le Bon finds the exhaustless source ofelectricity ..in the interior of atoms. The atomsin one pound of earth contain enough energy torun all the factories, mills, railroads, etc., andlight all the cities and villages of the UnitedStates, for a month, Steinmetz tells us. "It

would," he states further ("Relativity andSpace," ), "supply the fuel for thebiggest transatlantic liner for 300 trips fromAmerica to Europe and back. And if thisenergy of one pound of dirt could be let looseinstantaneously, it would be equal in destruc-tive powers to over a million tons of dyna-mite."

From the above statement, we may well un-derstand Dr. . Le Bon's interpretation of thework of a dynamo: "Matter being easily dis-

sociated and constituting an immense reser-

voir of intra-atomic energy, it is enough to ad-mit that the lines of force seized upon by theconducting body (the coils), which cuts themand causes them to flow in the form of anelectric current, are constantly replaced at theexpense of the intra-atomic energy. This latterbeing relatively almost inexhaustible, a singlemagnet can furnish an almost infinite numberof lines of force."

It can be Shown that the kinetic energy of


one kilogram (2.2 pounds) weight of matteris about 9000 millions of millions of kilogram-meters, or 25 thousand million kilowatt-hours(a kilowatt-hour=1000 watt hours). Thismeans, in other words, that the quantity ofenergy in the atoms of 2.2 pounds of ordinarymatter is thousands of million times greaterthan the energy of an equal quantity of coal,

released by chemical combustion. r

Estimating the total energy consumed duringthe year on earth for heat, light, power, etc.,

as about 15 millions of millions (—15,000,000,-000,000) of kilowatt-hours, Steinmetz tells usthat 600 kilograms, or less than two-thirds of aton, of "dirt," if it could be disintegrated intoenergy, would supply all the heat, light andenergy demand of the whole earth for a year.

Several eminent physicists are now specializ-ing on the problem of how to liberate andcontrol intra-atomic energy for man's uses—orabuses. Bearing in mind the present intel-

lectual, moral and economic status of our"leaders of thought" and their followers, andremembering that one pound of common soil

contains intra-atomic energy equal in destruc-tive power to more than a million tons of dyna-mite, let us hope that the secret of releasingand "controlling" intra-atomic energy will notbe discovered in our day and age.

CHAPTER 6

PROOF THAT ELECTRONS ARE ATOMS OFELECTRICITY

THE ZEEMA.N EFFECTHeinrich Hertz demonstrated in 1887 that he

could produce in the "ether"—or at least in


space—what are now known as "wirelesswaves," by allowing a charge of electricity to

oscillate to and fro. Larmor and Lorentz were,at the same time, endeavoring to formulate atheory which would account for the productionof the far shorter light-waves.Lorentz supposed that each atom contained

one or more iniinitesimal particles, or electric

charges (electrons), whose excessively rapidvibrations caused the emission of light-rays.Maxwell showed that there must be a close con-nection between light and electricity, a theoryconverted into demonstrable fact by the workof Hertz.That there is a similar relation between

light and magnetism was the firm convictionof Faraday. In 1845, he placed a block of verydense glass between the poles of the mostpowerful electromagnet produceable at thetime. Before turning on the switch, he alloweda beam of light tj pass through the glass, pro-ducing "polarization"—a modification of light-

rays resulting from their reflection (in this

case from a crystalline substance), impartingto the beam a definite direction—the plane of

vibration or plane of polarization. When theswitch was closed, permitting the flow of theelectric current, which produced the magneticfield, the beam of light was "rotated." That is,

the beam of light was "plane-polarized" by thecrystal, and "rotated" by the magnetic field;

i. e., now changed into two "circularly polar-ized" rays, one a left-handed motion and theother a right-handed motion (in the directionof the hands of a watch).

This could be accounted for only on the

16 PRINCIPLEB OF ELECTRICITY

theory that lig-t is affected by magnetism,since the beam was not rotated by the glassalone—in itself a very important discovery.But the experiment did not yield Faraday ananswer to the question uppermost in his mind:namely, can a magnetic field change the rateof vibration of a light-emitting particle? Thatis to say, in effect, can a magnetic field causea ray of light to shift its normal place in thespectrum?

It was not until 1862, seventeen years afterthe experiment just described, that Faraday at-

tempted to solve this important theoreticalproblem. He now placed a sodium flame in

front of the slit of the spectroscope, whichnormally yields two characteristic yellow lines

(the D lines of the spectrum), and observedthem with the best spectroscope at his com-mand, under the most powerful electromagneticfield which he could produce. No change fromthe normal coula be detected. Other observerstried the same experiment, but with negativeresults. We know that his theory was wellfounded, and that only the lack of a betterspectroscope and a more powerful magnet pre-

vented his discovery of what is now Known asthe Zeeman effect—a discovery which has al-

ready thrown a flood of light on a number ofdifficult physical problems.23

23For a good summary of the main results con-cerning the Zeeman effect, see von Auerbach, Felix,"Moderne Magnetik," Leipsic, 1921. An excellentaccount of the quantum treatment of the Zeemaneffect may be found in Chapter XV (Series Spec-tra) of Dr. N. R. Campbell's "Modern ElectricalTheory, Supplementary Chapters," Cambridge Uni-versity Press, 1921.


Working with much more powerful appara-tus, but following the same method of pro-

cedure employed by the immortal Faraday, Dr.Pieter Zeeman, of Leyden, succeeded, in 1896,

in experimentally demonstrating the close re-

lationship between light and magnetism. Dr.H. A. Lorentz, then Professor of Physics in

the University of Leyden, now mathematicalphysicist at the Norman Bridge Laboratory ofPhysics, Pasadena, California, had predicted thenature of the change in the spectral lines tobe expected, and this knowledge was used byDr. Zeeman as a check on his results.

Using a Rowland grating, instead of a less

efficient prism spectroscope, Dr. Zeeman foundthat when a relatively weak electric currentwas applied, the two sodium lines were merelywidened. In a still more powerful magneticfield, each of the lines was decomposed intotwo or three components, when the lines offorce were parallel to the line of sight. 24 More-over, the rays of the components of each line"were not those of natural light," but were"polarized in a characteristic way," i. e., were

24it seems that this phenomenon had previouslybeen observed by M. Fievez. (Cf. Miehelson, Dr.Albert A., "Light Waves and Their Uses," Page107.) "He thought that each separate line wasdoubled or quadrupled." Lockyer, in 1866, ob-

1 that some of the lines in a sun spot spectrumwidened. Prof. Charles Young and W. M.

Mitchell observed that some of the lines were evendouble, but it was not suspected that these phe-nomena were caused by a strong magnetic field insun-spots, brought about by free electrons beingdriven around in a vortex movement. In fact,Mitchell referred to the doublets as "reversals."


circularly polarized in opposite directions—"thedirection of the vibration depending in a sim-ple manner on the direction of the magneticlines of force."25

The same effect has more recently been pro-duced in the case of the spectral rays of nearly—if not quite—all the other elements. Theprocess, as described by Dr. George ElleryHale, is very simple: "We place our iron oreor spark between the poles of a powerful mag-net, and photograph its spectrum. The lines

behave in the most diverse way, some splittinginto triplets, others into quadruplets, quintup-lets, sextuplets, etc. One chromium line is re-

solved by the magnet into twenty-one com-ponents. . . . The distance between thecomponents of a line is directly proportionalto the strength of the magnetic field.26

The meaning of this splitting and polariza-

tion of light-rays in the magnetic field is that,

as Lorentz had predicted, there are present in

the luminous vapor vibrating particles nega-

25Zeeman, "Les Lignes Spectrales et les TheoriesModernes," Scientia, January 1, 1921, Page 18(Vol. XIX, No. CV—I).

26Hale, "Ten Years Work of a Mountain Ob-servatory," Pages 29-30, Washington, D. C. (Car-negie Institution of Washington), 1915. See also,Babcock, Harold D., "The Zeeman Effect forChromium," Contributions from Mount Wilson Ob-servatory, Vol. II, Paper No. 52 ; also "The Cor-respondence between Zeeman Effect and PressureDisplacement for the Spectra of Iron, Chromiumand Titanium," Arthur S. King, Loe. cit., Paper No.46 ; and "The Zeeman Effect on the Sun," Adriaanvan Maanen, Publications of the Astronomical so-ciety of the Pacific, Page 24, Vol. XXXIV, No. 197(February, 1922).


tively charged, or "electrons." Measurementof the distances apart of the components of

the triple line reveals the relation betweenthe charge and the mass of the particles. 27

It is interesting to add that the disturbancesin the magnetic field, as observed by Zeeman,were precisely of the amount calculated byLorentz purely on theoretical grounds, and themass of the electron was found by this methodto be 1/1840 that of the hydrogen atom. By adifferent method, Sir J. J. Thomson obtaineda value of 1/1800 the mass of the hydrogenatom; while Dr. Robert A. Millikan, by meansof his famous "electrical balance," derived avalue of 1/1845 that of the hydrogen atom.28

In his monograph of 1913, Zeeman remarkedthat in discoveries of optics "we may alwayscherish the hope that they will lead ultimatelyto applications to astronomy." So far as studyof solar phenomena and the Zeeman effect areconcerned, this hope has been fully realized,

and attempts are being made to extend the ap-plications of this method of investigation to

other stellar bodies. Of the general value of

Zeeman's discovery, Dr. Hale writes: "Thecomplex phenomena of the Zeeman effect (asrevealed in a comparative study, with powerfulspectrographs, and an intense magnetic field, of

the lines of a long list of elements) furnish ma-

27Zeeman, Loc. cit., Page 18. See also the clas-sical monograph by the same author, "Researches inMagneto-Optics," London, 1913.

llikan. Physical Review, 2, 143 (1913) ; "TheElectron," 1917 (revised edition, 1924). See also,Proceedings of the National Academy of Sciences.3, 314 (1917).

SO PRINCIPLES OF ELECTRICITY

terial available for wide generalization, im-portant in their bearing on theories of radiationand atomic structure" (Op. cit., Page 36).

Discovery by Hale and his co-workers atMount Wilson of the Zeeman effect in sun-spotsled to the very important conclusion that thesedisturbances represent whirling vortices ofelectrons, producing a magnetic field. "Thestrength of the magnetic field produced, whichis measured by the degree of separation of thetriple lines, increases with the diameter of thespot. ... It has long been known thatsun-spots usually occur in pairs, and our studyof the Zeeman effect indicates that the twoprincipal spots i-i such a group are almost in-

variably of opposite polarity" (Hale, Op. cit.,

Pages 28-31).

The sun, like the earth is now known to bea magnet, whose general magnetic field is about80 times as intense as that of the earth. Atthe distance of the earth the solar magneticfield is not appreciable, "since the effect of

one pole counteracts the equal and opposite ef-

fect of the other pole."

Were it not for our knowledge concerning theZeeman effect, it would not yet be known for

a certainty that the sun is a vast magneticglobe, since this fact could not be assumedto be a source of the sun's gravitational power."Indeed," says Dr. Hale,29 "its attraction can-

not be felt by the most delicate instruments at

the distance of the earth, and would still beunknown were it not for the influence of mag-netism on light. Auroras, magnetic storms,

29"The New Heavens," Page 70. New York, 1922.

-PRINCIPLES OF ELECTRICITY 51

and such electric currents as those that recently-

deranged several Atlantic cables are due, notto the magnetism of the sun or its spots, butprobably to streams of electrons, shot out fromhighly disturbed areas of the solar surface sur-

rounding great sun-spots, traversing 93 millionmiles of the ether of space, and penetratingdeep into the earth's atmosphere."

By means of the famous 150-foot tower tele-

scope at Mount Wilson, which produces at afixed point in a laboratory an image of thesun about sixteen inches in diameter, the mag-netic phenomena of sun-spots are being studiedtp great advantage, the enlarged sun-spots mak-ing possible separate observation of their vari-ous parts. "This analysis is accomplished witha spectroscope 80 feet in length, mounted in a

subterranean chamber beneath the tower." Bythis means the very important discovery wasmade by Director Hale that the entire sun, ro-

tating on its axis, is a great magnet. "Hence,"says Dr. Hale, "we may reasonably infer thatevery star, and probably every planet, is alsoa magnet, as the earth has been known to besince the days of Gilbert's kDe Magnete." Bar-nett has succeeded in producing magnetismby rapidly whirling masses of metal in the lab-oratory" (Hale, "The New Heavens," Pages 69-

70).

More recently (October, 1922), Hale, Eller-man and Nicholson, all of the Mount WilsonObservatory, have detected invisible sun-spotsby searching for evidences of the Zeeman ef-

fect in promising regions, such as areas offlocculi following a large spot. "A special


polarizing apparatus permits very small mag-netic fields to be found by the alternate widen-ing to red and violet of the iron triplet Lamb-da 6173," say Hale and Adams ("Summary of

the Year's Work at Mount Wilson," Publica-tions of the Astronomical Society of the Pacific,

October, 1922, Pages 269-70 [Vol. XXXIV, No.201]). "The results confirm the view that a

spot represents a vortex, which becomes visible

only when the cooling due to the expansion («f

gases) is sufficiently great to produce a per-

ceptible decrease in the brightness of the photo-sphere."From what has been said, it is evident that

Dr. Zeeman's desire to see the results of his

discovery applied to the study of astronomicalproblems has been fully realized.

THE STARK EFFECT

Lorentz's prediction regarding the effect of

a strong magnetic field on spectral rays, andthe movements of electrons in the field havingbeen confirmed so brilliantly by Zeeman, it

remained to ascertain what effect, if any, wouldbe exerted by electrical force on light-rays.

The answer to this problem was given byProf. Johannes Stark, at Aix-la-Chapelle, in

1913, by his skillful demonstration of the elec-

trical decomposition of the spectral rays of

hydrogen, helium and lithium. .30

Stark's task was a more difficult one thanZeeman's, owing to the fact that he had to deal

30Cf. Stark, "Die Atomionrn chcmischere Elementeund ihre Kanastrahlenspektra/* Berlin, L913. Seealso, "Elektrische gpektralanalyse chemischenA tome," Leipsic, 3 914.


with luminescent gases, which, being conduc-tors, exhaust the electrical field almost be-

fore any observations can be made, evenhurriedly. This condition gives rise to dif-

ficulties in connection with the application ofthe electric field. But these were very in-

geniously met by employment of highly evacu-ated tubes and the light emitted by the "canalrays"—positively charged particles similar to

the alpha rays. 31 Where the rays issue fromthe perforated electrode (or "canal"), the con-duction of electricity is weak, and Stark wasable to apply intense electric fields in a smallspace. It was then found that the diffuse raysof the spectrum produced were strongly influ-

enced, while the "sharp" rays were less so.

The attentive reader will note that this re-

sult was in marked contrast with the magneticdecomposition produced in the Zeeman experi-ment, in which tne rays did not differ one fromanother in respect to the degree of their de-composition. In all the details there is a dif-

ference between the electric and magnetic de-

compositions, and analogy existing only in this, '

namely, that in both cases polarized rays wereobtained. In both cases the results producedwere due to disturbance of the motions of elec-

trons, giving rise to broadening, displacementor other modifications of spectral laws. Both"effects" confirm the theoretical view of Max-

3iCalled "canal rays" by the German physicist,Eugen Goldstein, who, in 1886, first obtained themby th< perforated that is. he useda metallic tube for a cathode, thr< uph which tube,called by Goldstein a "canal," the n


well, namely, that light is an electro-magneticphenomenon.

Faraday's famous question is thus more thananswered in the affirmative: not only is therate of vibration of "atoms" (electrons)changed by a magnetic field, but also under theaction of an electrostatic field, producing de-

composition of certain spectral lines, which areusually polarized, as in the Zeeman effect.

As a result of his intensive investigations ofthe Zeeman effect, Dr. Henri A. Deslandres,Director of the Astrophysical Observatory at

Meudon (a southern suburb of Paris), pro-posed a new general formula which representsthe series relationship of the component lines

and heads of bands both for emission and ab-

sorption spectra. According to his experi-mentally-derived law, "the origin of these radia-

tions may be found in the transverse and longi-

tudinal vibrations of the atoms.

"

The lamented Dr. P. S. Epstein, a gifted pu-pil of Sommerfeld, who—like Mosely—fell «a

martyr to the World War, succeeded in apply-ing the quantum dynamics to the Stark effect,

whereby the motions of the electron in produc-ing the H-beta (in the blue-green) and H-gam-ma (in the violet) lines observed, "are ac-

counted for with great accuracy" (Loring,"Atomic Theories," Page 67).

It may be saia in conclusion, that the mostpromising attempts fully to explain the phe-nomena of the Zeeman and Stark effects seemto be made from the point of view of Planck'sQuantum Theory of Light. On the other hand,


it must be admitted that there has not been,so far as I can ascertain, any theory proposedwhich explains all of the phenomena involved.

CHAPTER 7

THE DISCOVERY OF WIRELESS TELEGRAPHYThe experimental foundation for the dis-

covery of wireless telegraphy was laid by theresearches of Faraday. '>-

Accepting Faraday's physical views as a pointof departure, James Clerk Maxwell (1831-1879),Professor of Experimental Physics in the Uni-versity of Cambridge, began (about 1860) thedevelopment of his constructive

tspeculations in

electrical theory which culminated in the nowuniversally accepted electromagnetic theory oflights

Fourteen years after the publication of Max-well's classic treatise, Heinrich Hertz (1859-

1894)—a brilliant pupil of Helmholtz (1821-

1894)—succeeded in producing electrical dis-

charges from a Leyden jar, which oscillationsin turn gave rise to electro-magnetic waves offar greater length than any previouslyknowHertz demonstrated also that the velocity of

propagation of these waves was the same asthat of light-waves—approximately 186,000

32See his "Experimental Researches in Elec-tricity," Everyman's Library Seri>

axwell, James Clark, "Treatise on Electricityand Magnetism," 1873.

34The theoretical investigation of the mode ofdischarge of a condenser had been given by SirWilliam Thomson (later Lord Kelvin) in 1853, inthe Philosophical Magazine for June of that year.


miles a second, equivalent to about seven timesthe circumference of the earth in one second.It was shown that the only difference betweenthe Hertzian ("wireless") waves, for example,and the light-waves, is in their respectivelength, or, reciprocally, their rates of vibrationper second. Hertz later demonstrated thatthese invisible waves produced by a Leydenjar could be reflected, refracted, and pola-rized, as in the case with the far shorter light-

waves or rays.35 These results had been pre-

dicted by Maxwell.

In this great discovery the foundation forwireless telegraphy and wireless telephony waslaid—for Hertz had found what are now knownas "wireless" or radio waves—destined, per-haps, to revolutionize our methods of obtainingpower for machinery, and for transportation, asthey have already revolutionized our methodsof communication. Hertz had done more thanthis: for his investigations made possible afar more satisfactory research into the struc-

ture of atoms.

"If we were asked to pick out one date that

35When all the atoms and molecules of a sub-stance vibrate in one plane, e. g., as the plane of atrain of waves would be if drawn on this page, thewave is said to be polarized. Ordinarily, light-rays are sent out from particles vibrating in dif-ferent planes ; they may be vertical or horizontal,or diagonal, or they may move in a curved path

—

circles or ellipses. Ordinary light-vibrations aremixed up together, vibrating in all planes, and spe-cial devices—"polarizers"—are required in orderto separate any one particular vibration from therest.


stands out more prominently than others in

our acquisition of knowledge bearing upon thestructure of matter," says Dr. Albert C. Cre-

hore, "it might be this epoch-making work ofHertz."36

While it is true that the waves that Hertzdiscovered and measured "differ from light-

waves merely in wave-length or period of vibra-tion and quality," on the other hand the dif-

ference in wave-length is so great that no in-

strument had as yet been devised to measure ordetect waves that were meters long, as com-pared with light-waves but a minute fractionof a centimeter in length.

It was Hertz's task—following up Maxwell'sprediction—to devise an instrument whichwould detect waves not cognizable by oursenses alone. For this purpose he used asimple loop of wire with the ends brought neartogether, each terminating in a metal ball.

When these balls were brought almost into con-tact, a small electrical spark was seen to passbetween the balls when the "oscillator"—theapparatus used to generate the oscillating cur-rents, or electric waves, of high frequency

—

was set in operation.- 7

Hertz not only proved that the speed of

electric waves is the same as that of light,

and that they are subject, under certain con-

36Crehore, Dr. Albert C, "The Mystery of Matterand Energy," Page 28, New Fork, 11)17.

37By means of an induction coil coupled to acircuit containing capacity terminals, thus formingan "oscillatory circuit."


ditions, to "interference" as are light-waves,but he also succeeded in actually measuringthe length of the waves produced by his crudeapparatus. This was accomplished by produc-ing what are known as "standing waves," ana-logous to the sound-waves produced by anorgan-pipe. Moving his detector slowly alongthe wire, Hertz observed that the spark wouldappear when a certain interval of space wasreached, and as he continued to move thedetector the sparks would disappear and re-

appear at regular distances. He rightly con-cluded that these points of disappearance andreappearance of the spark corresponded to thenodes and loops of the "standing waves,"representing the wave-length of the electrical

undulations.

It has since been established that the dif-

ference in wave-length between the electric

undulations produced by Hertz and those oflight-waves may be enormous or quite moder-ate. Professor Michelson tells us that "a tele-

graphic wave, which is practically an electro-

magnetic disturbance, may be as long as 1000miles. The waves produced by the oscillations

of a condenser, like a Lyden jar, may be asshort as 100 feet; the waves produced by aHertz oscillator may be as short as one-tenthof an inch. Between this and the longest light-

wave there is not an enormous gap, for the lat-

ter has a length of about 1/1000 inch. Thusthe difference between the Hertz vibrationsand the longest light-wave is less than the dif-

ference between the longest and shortest light-

waves, for some of the shortest oscillations are

PRINCIPLES OF ELECTRICITY Sv

only a few millionths of an inch long. Doubt-less even this gap will soon be bridged over. 3s

The Hertz apparatus was greatly improvedby Auguste Righi, in the University of Bologna.In the same class in physics was Marconi, whobegan his fruitful experiments in 1895, oneyear after Sir Oliver Lodge had perfected thecoherer. Lodge's coherer, used by Marconi inhis early work, consisted of a glass tube con-taining a pinch of nickel and silver filings inequal parts. Crude as this detector was,judged by present-day standards, it materiallyimproved the conductivity of contact metals in

the case of Hertzian waves.

In 1S99 wireless communication was estab-lished across the English Channel, and in 1902Marconi sent the first wireless message fromEngland to America. Today, wireless wavesmeasuring miles from crest to crest are beingemployed in the transmission of messages frompoints separated by thousands of miles, andthe human voice has already been carriedacross the Atlantic by radiophone, but only inone direction.

The wireless sending and receiving stationof the Dutch government, at Kootmyck, in theProvince of Gelderland, is equipped to employa 12,000-meter wave-length in sending and re-

ceiving simultaneously messages between Hol-land and Java, 7,500 miles distant. It has the

3SMichelson, Dr. A. A.. "Light Waves and TheirLTses," Pages 160-61. The gap was closed duringthe year 1924, heat-waves being measured whichwere of such great length as to merge into theshortest Hen/ian v,«* "wireless" waves.

€0 PRINCIPLES OF ELECTRICITY

same capacity as our Long Island (RockyPoint) station, and is therefore one of thebiggest in the world.On December 19, 1922, a long distance phono-

graph which records sounds made hundreds ofmiles away was demonstrated to the Societyof Western Engineers, by E. H. Colpitts, of theWestern Electric Company. The transmissionof electric power by radio is as yet but adream; but it is a dream which may come truewithin the next five years.39

Signals are now being received from stationssituated at distances as great as 12,000 miles,made possible, it is believed by the existenceof an electrical conducting layer—electrified

dust expelled by the sun—some 150 miles indepth, the bending of the radio-waves aroundthe earth being caused by diffraction. Someunknown factor is operating to give the signalsa strength millions of times greater than canbe accounted for at present by any plausibletheory, according to Prof. J. A. Fleming (FifthHenry Truman Wood Lecture before the RoyalSociety of Arts, London, 1922).

It is not reasonable to assume that no otherelectromagnetic waves remain to be discovered.We may yet hear "the roar of the sun-spots,"though Edison's experiments along this line

were unsuccessful. What, indeed, were themysterious "signals" occasionally reported ashaving been received at Marconi wireless sta-

tions—registered, it was reported in the press,

3SSee an interesting article on this question inScience and Invention, December, 1922, Page 744k(Vol. X, Whole No. 116).


"only when a minimum of sixty-five-mile wave-lengths had been established," but waves issu-

ing from the mighty sun, 93,000,000 miles dis-

tant? However, Marconi tells us that one ofthe "signals" comes as three short raps—"S"in the Morse code. He believes that these"signals" may have been sent out from Marsor Venus. Similar mysterious "signals" werereported by wireless stations in different partsof the world during the apposition of Mars in

August, 1924.

"Outside of the radio-waves that are floatingabout there may be hundreds of others whichwe have not as yet been able to register. . . .

There may be many other waves coming to uafrom the sun, of which we have no knowledgetoday. . . . The human ear cannot hearbelow eight vibrations per second and not high-er than about 30,000 vibrations per second.Certain animals can hear below and above thatscale. By means of our vacuum tubes certainresearches indicate that a tremendous amountof noise goes on below the eight vibrations persecond, and still more noise above the 30,000

vibrations. Entirely new worlds lie in thesetwo directions, of which nothing is knowntoday. The vacuum tube is likely to solve

these mysteries and take us into the unchartedworlds, far into the unknown, within the nextfew years. "^o

In March, 1922. the late Dr. Charles P. Stein-

metz said that he considered well founded tne

supposition that performances of low-power

40Gernback. H., Editorial in Science and Inven-tion, December, 192


radio sending apparatus in transmitting mes-sages to surprising distances gave an indica-tion that the radiations peculiar to wirelesstransmission pass with equal ease through theearth or through the "ether."

Such radiations would be in accordance withaccepted electrical laws, as the ground, towhich both the sending antennae and the re-

ceiving set are connected, would act as a re-

turn circuit for the current. Similarly, watermight serve as a medium for radio conversa-tions between ships, or between ships and the-land.

Moreover, it was announced during the samemonth that wireless telephony had beenrevolutionized by the successful performancesof the duplex transmitters which the GeneralElectric Company had just completed. Con-versations were held between New York andpassengers aboard the steairier "America,"which, at the time, was at a distance of 360miles from shore.

The three-electrode audion or vacuum tubewas perfected in 1912, making radio-telephonypossible. In 1921, Reginald A. Heising, a youngphysicist working for a degree of Master of

Science at the University of Wisconsin, con-

ceived the brilliant idea of putting into the

vacuum tube the amount of energy producedby the voice, and then getting it out manytimes amplified in the form of high-frequencypower in the antenna. This problem he soonsolved, so far as the principle of the modula-tion system was concerned, and in 1922 the


practical problem was worked out and themethod all but perfected.

All these great utilitarian advances have beenmade possible by the researches of men inter-

ested in the advancement of knowledge for its

own sake. As has been pointed out recentlyby Dr. Hale ("The New Heavens," Pages 87-

88), "Faraday, studying the laws of electricity,

discovered the principles which rendered thedynamo possible. Maxwell, Henry and Hertz,equally unconcerned with material advantage,made wireless telegraphy possible. . . . Wire-less telephony and transcontinental telephonywithout wires were both rendered possible bystudies of the nature of the electric dischargein vacuum tubes."

In an interview in December, 1922, Dr. NikolaTesla gave it as his opinion, based upon experi-ments already carried out in his own laboratoryin New York City, that power flashed throughspace by radio will soon be employed in all

the world's activities.

"Besides bridging enormous distances in

flight and wireless conversation," he said,

"modern science will span the earth withpower flashed through the air by radio. Air-planes and ships and trains will carry no fuel,

but will run by transmitted energy. Withwireless power no one—explorers, travelers,campers—need be cut off from civilization andits comforts.

"Not only that, but we shall see at greatdistances by aid of wireless energy. And see-ing our neighbors across the oceans will makefor a united social and political world."

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